The waterjet cutting process includes utilizing a stream of water with high pressure to erode a narrow line in the subject material. EDM stands for Electrical Discharge Machining, which is used to machine electrically conductive materials. To learn more about “Waterjet VS EDM Cutting” and to discuss their pros and cons, let’s take a look at each of them in detail.
Waterjet Cutting:
This method includes a stream of water with a pressure of almost 50,000 to 60,000 PSI to cut through metals or even non-metals. Newer waterjet systems are able to reach a pressure of 90,000 PSI. These high pressures can cut through almost any material. This high-pressure stream of water is used to cut a narrow line in between the material used.
For harder materials, an impurity or granular abrasive substance is added to the water stream to cut through them. This is known as an abrasive waterjet cutting method. This material helps erode the materials that are tough to cut with a simple water stream.
Must Read: Abrasive VS Pure Water Jet Cutting
The waterjet cutting method is used widely in the industry due to its ability to cope up with changes. The accuracy of this method can be increased by increasing the pressure of the stream. It can also be achieved by adding a nozzle at the output. This helps improve the results of the machine.
Micro Waterjet cutting is an advanced method for the cutting of materials on a micro-level. This method uses a lesser nozzle diameter which results in more accurate and small cuts.
Another technique used for cutting more complex parts is known as 3D Waterjet cutting. This method includes the moving of the head, which is applying a pressure stream to the material. The cutting can be done in three dimensions which helps produce 3D parts instead of planar material cuttings.
The CNC Waterjet Machines has made it easier for the operator to achieve the final results and improve productivity. As it is well understood that these methods take time to finish, the CNC methods have provided a lot of ease to the owners.
Now let’s look into some of the features of Waterjet cutting.
Accuracy:
This method yields an accuracy of almost ±0.003”. More accuracy can be achieved by using advanced software in the operating machines. Better operating systems can yield better results.
Thickness:
Waterjet cutting machines are able to cut under 3” thick parts. Thicker parts can be cut with lesser accuracy or speed.
Cutting Speed:
The average cutting speed of a nominal waterjet cutting machine is known to be around 760 m/s. The high-pressure stream of water makes the process really fast and lesser time-consuming.
Heat Affected Zone (HAZ):
There is almost no HAZ in this method as this uses pure water and no heating elements. This helps improve the quality of the products.
Quality of Edge:
The quality of the edge of the product is proven to be good when a waterjet cutting method is used.
Material Distortion:
This method does not distort the materials and does not change any properties of the materials used.
EDM Cutting:
Electrical Discharge Machining is a much more precise and accurate method to cut through materials that are conductive. It uses a series of sparks to cut through metals and other conductive materials.
The basic EDM process includes the electrical spark between an electrode and a conductive workpiece. The spark then erodes the material, making way for the cut. This electric discharge generates about 8000-12000 degrees of heat.
An advanced technique in EDM cutting is to use a wire to cut through the materials. The wire is electrified and is brought near to the material. The current in the wire will produce a spark with the material making way for the wire. In this way, the wire moves along a defined path and cuts through the material.
The wire Edm method is proven to be more accurate than the basic EDM cutting. The wire provides good accuracy while cutting. There are mainly two ways to cut through the material with the wire EDM. They are One-Cut Method and Skim-Cut Method.
A One-cut method means that the wire will pass through the material only once, which will result in some slug dropping or remaining on the edges of the material. This results in making rough edges for the product. In most cases, skimming is required to smoothen out the end product according to desires.
A Skim-Cut method includes multiple rounds of the wire going through the same path and making the cuts smoother than before. The minimum rounds in this method are two. But, as the rounds increase, the smoothness of the surfaces increases. A skim cut is said to have up to 9 rounds.
Let’s look into some basic features of this method.
Accuracy:
Wire EDM Cutting is more accurate and provides an accuracy of ±0.0001”. The wire used to erode the material serves the purpose of accuracy.
Thickness:
In the case of EDM cutting, the thickness of the parts can be up to 12”. The wire’s length can be increased to achieve more thick cutting, but the accuracy will have to be compromised for this purpose.
Cutting Speed:
The average cutting speed of an EDM cutting machine is 18”-20”/hour. This speed is set for an average EDM cutting machine.
Heat Affected Zone (HAZ):
This process uses electrical discharge to generate high temperatures for cutting. So, there will be HAZs to some extent in the material that is under process.
Quality of Edge:
The quality of the edge of the cut is proven to be excellent when this process is used. The material turns into a very fine product after the process is finished.
Material Distortion:
The sole purpose of this process is to cut by melting the material. This results in heat distortions in the material and can change the properties of the material to some extent. But the distortion is negligible as it does not affect the appearance and durability of the material.
Waterjet VS EDM Cutting: Which is Better?
A waterjet cutting machine can be considered seemingly fast as compared to the EDM cutting machines. The waterjet machine provides more pieces/hour than the EDM machine.
Both machines are well known for their accuracies, but EDM machines win in case higher accuracy is required. The waterjet method can be considered only when the tolerances are not extreme.
On the other hand, the benefits of water jet cutting are incredibly great as it can cut almost any material., whereas the EDM machine is specifically required to cut through only conductive materials.
The waterjet cutting method is widely used in the industry as it is extremely fast, and there is room for improvement. The EDM method is said to have no room for such improvements, and accuracy cannot be increased by making any changes.
The advantages and disadvantages of the two methods discussed indicate clearly that for mass production of cut parts or if the product needs to be produced at a higher rate, the Waterjet method is proven to be more successful than the EDM cutting method. The Waterjet cutting method can be a bit expensive as it requires more maintenance and supervision than the EDM Cutting machines, but their success in the industry shows us how efficient a waterjet cutting machine is.
So if any industry is looking for cutting machines, the waterjet cutting machine is the best option to opt for. This will yield better and faster production than any other method.
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